Results 41 to 50 of about 75,052 (218)
Variational methods in loop quantum cosmology [PDF]
Europhysics Letters (EPL), 2006 An action functional for the loop quantum cosmology difference equation is presented. It is shown that by guessing the general form of the solution and optimizing the action functional with respect to the parameters in the guessed solution one can obtain approximate solutions which are reasonably good.
F. Shojai, Ali Shojai
openalex +6 more sources
Noncovariance of the dressed-metric approach in loop quantum cosmology [PDF]
Physical Review D, 2020 The dressed-metric approach is shown to violate general covariance by demonstrating that it cannot have an off-shell completion in which the correct infinitesimal relations of space-time hypersurface deformations are realized. The main underlying reason--
M. Bojowald
semanticscholar +1 more source
The time-dependent mass of cosmological perturbations in loop quantum cosmology: Dapor–Liegener regularization [PDF]
Classical and quantum gravity, 2020 In this work, we compute the time-dependent masses that govern the dynamics of scalar and tensor perturbations propagating on an effective flat, homogeneous, and isotropic background within the framework of loop quantum cosmology (LQC), regularized ...
Alejandro Garc'ia-Quismondo +2 more
semanticscholar +1 more source
Quasi-probability distributions in loop quantum cosmology [PDF]
Classical and quantum gravity, 2020 In this paper, we introduce a complete family of parametrized quasi-probability distributions in phase space and their corresponding Weyl quantization maps with the aim to generalize the recently developed Wigner–Weyl formalism within the loop quantum ...
J. Berra-Montiel, Alberto Molgado
semanticscholar +1 more source
Primordial perturbations in the Dapor-Liegener model of hybrid loop quantum cosmology [PDF]
, 2020 In this work, we extend the formalism of hybrid loop quantum cosmology for primordial perturbations around a flat, homogeneous, and isotropic universe to the new treatment of Friedmann-Lemaitre-Robertson-Walker geometries proposed recently by Dapor and ...
Laura Castelló Gomar +2 more
semanticscholar +1 more source
Polymer Dynamics of Isotropic Universe in Ashtekar and in Volume Variables
Universe, 2022 We analyze the semiclassical and quantum polymer dynamics of the isotropic Universe in terms of both the standard Ashtekar-Barbero-Immirzi connection and its conjugate momentum and also of the new generalized coordinate conjugate to the Universe volume ...
Eleonora Giovannetti +3 more
doaj +1 more source
Does the Loop Quantum μo Scheme Permit Black Hole Formation?
Universe, 2021 We explore the way different loop quantization prescriptions affect the formation of trapped surfaces in the gravitational collapse of a homogeneous dust cloud, with particular emphasis on the so-called μo scheme in which loop quantum cosmology was ...
Bao-Fei Li, Parampreet Singh
doaj +1 more source
Universe, 2022 The hybrid and the dressed metric formalisms for the study of primordial perturbations in Loop Quantum Cosmology lead to dynamical equations for the modes of these perturbations that are of a generalized harmonic-oscillator type, with a mass that depends
Simon Iteanu, Guillermo A. Mena Marugán
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An Overview on the Nature of the Bounce in LQC and PQM
Universe, 2021 We present a review on some of the basic aspects concerning quantum cosmology in the presence of cut-off physics as it has emerged in the literature during the last fifteen years.
Gabriele Barca +2 more
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Gauge-Invariant Perturbations at a Quantum Gravity Bounce
Universe, 2022 We study the dynamics of gauge-invariant scalar perturbations in cosmological scenarios with a modified Friedmann equation, such as quantum gravity bouncing cosmologies.
Steffen Gielen, Lisa Mickel
doaj +1 more source